JPH07137148A - Manufacture of fiber reinforced resin article, and mold used in the manufacture - Google Patents

Abstract

PURPOSE:To keep the wall thickness of a prefoamed pliable sheet constant and thus obtain a uniform article readily by placing reinforcing fiber within a mold cavity and attaching a prefoamed pliable sheet, and then by pressurizing nylon resin from the outside via the pliable sheet to be impregnated into the reinforcing fiber CONSTITUTION:After putting fiber reinforced material 13 within the mold surface 12 of a lower mold 11, a pliable sheet of acrylic latex is spread over thereon, and the peripheral part thereof is fixed on the upper surface of the lower mold 11 by means of a securing plate. Then, compressed air is Introduced therein from the compressed air inlet 16a so as to press the prefoamed part 14b of the pliable sheet 14 against the fiber reinforced material 13. Namely, the mold surface and pliable sheet 14 serve to define a cavity 15 with fiber reinforced material 13 filled therein. Following this, the mold !s subjected to temperature up, and decompression is effected through a discharge port 19 or an injection port 20. Next, RIM nylon is melted to be infected from the infection port 20, and further the pliable sheet 14 is applied by a secondary pressure in order to discharge surplus resin from the discharge port 19 through a resin reservoir 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fiber-reinforced resin product and a molding die used in the method, and more particularly,
Unreacted RIM after placing reinforcing fibers in the cavity
It is preferably used for producing a molded article having a high fiber content and a complicated shape by a reaction injection molding method in which a nylon resin is injected into a cavity to cause a reaction while impregnating a reinforcing fiber.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a fiber reinforced resin product of this type by a reaction injection molding method, the applicant of the present invention, as shown in FIG. The flexible sheet 3 is used for at least a part, and the reinforcing fibers 5 are arranged in the cavity 4 surrounded by the mold surface, and then the flexible sheet 3 is covered and fixed to the mold 1 to provide flexibility. A cavity surrounded by the sheet 3 and the mold surface 2 is formed, and pressurized air is externally applied to the flexible sheet 3 from the inlet 6, and the cavity is inserted into the cavity 4 through the flexible sheet 3. There is provided a method of pressurizing the reinforced fibers 5 arranged and injecting an unreacted raw material liquid into the cavity through an injection port 7 to cause a reaction while impregnating the raw material liquid into the reinforced fibers. (JP-A-3-272820, Japanese Patent Application No. 3-2728)
(No. 92)

As the flexible sheet 3, nylon,
A flexible material such as cellophane, rubber, polyester, polyetherketone is used, and silicon rubber is most preferably used in consideration of mold releasability, polymerizability, heat resistance, strength and the like. .

[0004]

The manufacturing method using the above-mentioned flexible sheet has a problem that the excess resin is not sufficiently discharged and the thickness and weight of the molded product vary greatly. That is, when RIM nylon or cyclopentadiene for reaction injection molding is used as the matrix resin,
The molding was completed while the reaction time of the unreacted raw material liquid was short and the resin amount was large relative to the amount of the reinforcing fibers in the cavity, that is, the surplus resin was not sufficiently discharged. In that case, as shown in FIG. 4, there is a drawback that the molding is completed in a state where the resin-only portion Z is partially generated on the mold surface side, and the weight and wall thickness become unstable. This is particularly noticeable when a resin having a short polymerization time is used.

As a solution to the above problem, a flexible sheet is preformed into a shape corresponding to the shape of the inner surface of the product in advance, and the gap between the flexible sheet and the mold surface is reduced. Then, the expanded flexible sheet quickly pressurizes the inside of the cavity, so that the resin can be smoothly flowed to the discharge port while permeating the reinforcing fiber from the injection port to sufficiently discharge the excess resin. preferable.

As described above, the flexible sheet 3'to be preformed needs to be preformed into the shape shown in FIG. 6 when manufacturing the helmet shown in FIG. 5, for example. The flexible sheet 3'has a substantially hemispherical projecting portion 3a 'in its central portion, and a mold fixing portion 3c' extending outward in a sheet state from its open end 3b '.

The above preformed flexible sheet 3 '
7 is formed of silicon rubber, as shown in FIG. 7, a sheet-shaped silicon rubber is divided, and the divided silicon rubber sheet 3b ″ is attached to the outer peripheral surface of the model 5 to form the sheet 3b ″.
The end portions of the are overlapped and stuck together, and vulcanized in this state,
The preformed flexible sheet 3 ′ shown in FIG.

However, as described above, it is very troublesome to attach the sheet to the spherical surface, and it takes a long time of 2 hours or more to form the preformed flexible sheet 3 '. There is. In addition, there is a drawback that the thickness of the portion where the above-mentioned sheets are stuck together becomes large and the stretch of the preformed flexible sheet becomes uneven. Molding using this flexible sheet with non-uniform elongation makes it possible to obtain a homogeneous molded product in which the resin-rich part and the resin lean part exist in the molded product, and the reinforcing fibers are uniformly impregnated with the resin. There is a drawback that can not be done.

The present invention has been made in view of the above problems, and provides a mold provided with a flexible sheet which is easily preformed and has a uniform thickness and uniform elongation. It is an object of the present invention to provide a method for producing a fiber-reinforced resin product using a mold equipped with a flexible sheet.

[0010]

In order to achieve the above object, the present invention provides a method for producing a fiber reinforced resin product using a nylon resin for reaction injection molding as a matrix, which is provided along a mold surface in a cavity of a mold. Place the reinforcing fibers, then
A flexible sheet preformed into a shape corresponding to the shape of the inner surface of the product, at least the surface layer of which is the cavity mold surface, made of acrylic latex, is attached to the mold so that it constitutes a part of the mold cavity, and no reaction occurs. Nylon resin for reaction injection molding (RIM nylon resin) is injected into the cavity, and then the flexible sheet is pressed from the outside,
A method for producing a fiber-reinforced resin product, in which a RIM nylon resin in a cavity is pressed through the flexible sheet to cause the RIM nylon resin to permeate the reinforcing fibers to cause a reaction and to be molded.

As the pressure medium applied to the inside of the cavity through the flexible sheet, an isotropic pressure medium such as gas such as compressed air or liquid is used. The pressure applied through the flexible sheet is the primary pressure applied before and during the injection of the RIM nylon resin, and the secondary pressure applied after the injection of the RIM nylon resin until the completion of the solidification of the RIM nylon resin. It is preferable to set the secondary pressure to be higher than the primary pressure and the injection pressure of the RIM nylon resin. In particular, the primary pressure is P1,
When the secondary pressure is P2 and the injection pressure of the RIM nylon resin is Q, it is preferable to set so that all of the following three equations are satisfied. P1 ≦ Q, 1.2 × P1 <P2, Q <
P2 Further, it is also effective to depressurize the inside of the cavity in which the reinforcing fibers are arranged in consideration of the resin permeability.

According to the present invention, a fiber-reinforced resin molded product is also prepared by arranging reinforcing fibers in advance in a cavity of a mold and then injecting a RIM nylon resin into the cavity to cause a reaction while impregnating the reinforcing fibers. As a mold for producing the above-mentioned cavity, the cavity is formed by surrounding the mold surface of the mold and a flexible sheet which fixes reinforcing fibers in the mold surface and then fixed to the mold. Preform the sheet into a shape corresponding to the inner surface shape of the product and at least form the surface layer that becomes the cavity mold surface with acrylic latex,
Further, the present invention provides a mold for producing a fiber-reinforced resin molded product, characterized in that it is provided with means for externally pressing the flexible sheet.

The preformed flexible sheet is formed by immersing a preform model in a melt of acrylic latex, pulling it out of the melt, allowing it to dry naturally, and curing it. As described above, the use of acrylic latex as the flexible sheet has excellent heat resistance,
This is because it does not hinder the polymerization reaction of the RIM nylon resin. Therefore, it is not always necessary to mold the entire flexible sheet with acrylic latex, and the heat resistance is excellent, but R
The surface of another latex that inhibits the polymerization reaction of the IM nylon resin, that is, the surface which becomes the cavity mold surface in contact with the RIM nylon resin may be coated with acrylic latex. In that case, for example, it is immersed in a melt of natural rubber latex, pulled up and naturally dried, then immersed in a melt of acrylic latex, pulled up and naturally dried.

In the present invention, the reinforcing fibers to be placed in advance in the cavity are carbon fibers in the form of continuous fibers, long fibers or short fibers, glass fibers, aramid fibers, silicon carbide fibers, regardless of form and type. Steel fibers, amorphous metal fibers, organic fibers and / or mixtures thereof are preferably used.

Further, the RIM nylon resin used in the present invention is molded by a monomer casting method in which molten lactams containing a polymerization catalyst and a polymerization initiator are injected into a mold, and the resulting lactams are polyamide-polymerized by heating. It

As the above-mentioned ω-lacmuta which is a monomer, α-pyrrolidone, α-piperidone, ω-enanthlactam, ω-caprolactam, ω-caprylactam,
ω-pelargonolactam, ω-decanolactam, ω-undecanolactam, ω-laurolactam, c-alkyl-substituted-ω-lacmuta thereof, and a mixture of two or more kinds of these ω-lacmuta. Also,
The ω-lacmuta may contain an improving component (soft component), if necessary. The soft component is a compound having a functional group that reacts with the initiator used in the molecule and has a low Tg, and a polyether having a normal functional group, liquid polybutadiene, or the like is used.

Commercially available raw materials used as the above-mentioned ω-lacmuta include UBE nylon (UX manufactured by Ube Industries, Ltd.).
-21) etc. It is composed of an A component consisting of an alkali catalyst and caprolactam, a prepolymer containing a soft component and a B component consisting of caprolactam.

As the above-mentioned polymerization catalyst, sodium hydride is preferable, but other known .omega.-lacmuta polymerization catalysts such as sodium, potassium and thylium hydride can be used. The amount added is 0 with respect to ω-lacmuta.
The range of 1-0.5 mol% is preferable.

As the polymerization initiator (activator), N-
Acetyl-ω-caprolactam is used, but other triallyl isocyanurates, N-substituted ethyleneimine derivatives, 1.1′-carbonylbisaziridine, oxazoline derivatives, 2- (N-phenylbenzimidoyl) acetanilide, 2- (N-Phenylbenzimidoyl) acetanilide, 2-N-morpholino-cyclohexene-
A compound such as 1.3-dicarboxanilide or a known isocyanate or carbodiimide can be used.
The amount of the polymerization initiator added is preferably within the range of 0.05 to 1.0 mol% with respect to the amount of ω-lactam.

[0020]

According to the above-described manufacturing method of the present invention, the RI
Since a flexible sheet having at least a surface of acrylic latex that does not inhibit the reaction of the M nylon resin is used for molding, the nylon solidified on the side in contact with the flexible sheet has stable quality and is a manufactured product. The performance of can be improved. Further, since the flexible sheet is pre-formed into a shape corresponding to the shape of the product in advance, the pressure inside the cavity can be quickly raised to a required pressure when expanded by pressurization, and the flexible sheet is injected into the cavity. RIM nylon resin can be smoothly flowed to the outlet side while permeating the reinforcing fiber. Therefore, the excess resin can be sufficiently discharged before being solidified, and a molded product having a required thickness and weight can be manufactured.

Further, since the above-mentioned flexible sheet is formed simply by immersing the model in acrylic latex, then pulling it up and naturally drying it, compared with the case where a conventional silicone rubber sheet is attached to the model. It can be easily installed in a short time. Moreover, the thickness of the molded flexible sheet is constant, the elongation becomes constant when pressurized and expanded, and a resin-rich portion and a resin-lean portion occur when the elongation becomes uneven. You can eliminate the drawbacks.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a mold according to the present invention, and the mold 10 is
A lower die 11 is provided with a die surface 12 which is recessed in a hemispherical shape at the upper surface opening. On the upper surface of the lower mold 11, after placing the fiber reinforcement 13 in the mold surface 12, the flexible sheet 14 is covered, and the peripheral edge of the flexible sheet 14 is placed on the upper surface of the lower mold 11. The holding plate 16 is covered and fixed with a fastener (not shown). That is, the flexible sheet 14 constitutes an ordinary mold upper die, and the cavity 15 is formed by the flexible sheet 14 and the lower die surface 12.

The mold lower die 11 is provided with an unreacted raw material liquid injection port 20 which is opened at the lowermost position of the mold surface 12, while the upper surface communicates with the resin reservoir 18 and the resin reservoir 18. A discharge port 19 is provided. Also, the above-mentioned pressing plate 1
6 is provided with a compressed air inlet 16a, and a compressed air supply pipe 17 is connected to the compressed air inlet 16a so that the flexible sheet 14 can be pressurized with compressed air.

The flexible sheet 14 has the same shape as that shown in FIG. 6, and is inserted into the peripheral sheet-shaped mold fixing portion 14a to be placed on the upper surface of the lower die and the hemispherical concave portion of the lower die 11. It has a central preform part 14b. In this embodiment, since the helmet is molded, the mold surface 12 of the lower mold 11 has a hemispherical shape, and the preform portion 14b inserted and arranged inside the mold surface 12 has a required distance L from the mold surface 12. It is a hemispherical protrusion that runs along.

As for the flexible sheet 14, as shown in FIG. 2, the model 5 shown in FIG. 7 is immersed in a solution tank 20 of acrylic latex. Then, pull it up from the solution tank 30,
Acrylic latex coated with the required thickness on the surface of the model is naturally dried and cured to form a rubber film. The rubber film becomes the flexible sheet 14. As described above, by using the dipping method, the preform portion 14b having a required complicated shape is formed.
Can be formed very easily. Moreover, the wall thickness of the flexible sheet can be made uniform and the elongation rate can be made constant. In the case of the above dipping method, the time required for forming the preformed flexible sheet 14 is 30 minutes, which is about 1 / th that of the case where the above-mentioned silicone rubber sheets are stuck together.
It was 4 hours.

A hemispherical shell-shaped molded product (helmet) was molded as follows using the above-mentioned mold. Lower mold surface 12
Along the arc surface of the glass fiber cloth (Nittobo WEA
18K105BZ) was placed.

Then, a flexible sheet 14 of acrylic latex product having a thickness of 1.3 mm was fixed to the upper surface of the lower die 11 of the mold together with the pressing plate 16. Fibers arranged along the mold surface 12 by pressing the flexible sheet 14 with compressed air injected from the compressed air injection port 16a at 2 kg / cm ² to press the preform portion 14b of the flexible sheet 14. It was pressed against the reinforcement 13. That is, as shown in FIG. 1, the mold surface 12 and the flexible sheet 14 form a hemispherical shell-shaped cavity 15 filled with the fiber reinforcing material 13. The temperature of the mold was raised to 150 ° C., and the discharge port 19 or the injection port 20 was connected to a decompression source (not shown) to reduce the pressure in the cavity 15 to 5 mmHg.

Next, RIM nylon (UX manufactured by Ube Industries)
-21) is melted at 90 ° C., mixed and stirred,
It was injected from the injection port 20. After injecting a predetermined amount of RIM nylon, a secondary pressure was applied to the flexible sheet 14 to pressurize the flexible sheet 14, the excess resin was accumulated in the resin reservoir 18, and then discharged from the discharge port 19.

Polymerization was completed within 2 minutes after the injection, the flexible sheet 14 was removed and the mold was released, and a molded article composed of a helmet was taken out. The helmet weighed 710 g.

When a molded article made of the above helmet was cut and analyzed, the presence of an excess resin portion was not recognized and the thickness was uniform.

An experiment was conducted to compare a flexible sheet made of the acrylic latex of the present invention with a flexible sheet made of another rubber latex. That is, natural rubber latex,
Flexible sheets were formed from SBR latex, NBR latex, chloroprene rubber latex, and urethane rubber latex, respectively, and attached to the mold shown in FIG. Similarly, a helmet made of fiber reinforced resin having RIM nylon as a matrix was molded.

Molded articles were measured in terms of their effect on heat resistance and the polymerizability of the RIM nylon resin. In terms of heat resistance, natural rubber latex, SBR latex and NBR latex did not retain their original shape after molding. When chloroprene rubber latex and urethane rubber latex were used repeatedly, they became aged from the fifth time and could not be used. Only the flexible sheet made of acrylic latex can be used while retaining its original shape even after repeated use. That is, the heat resistant temperature of acrylic latex is 200
℃, 180 ° C for chloroprene rubber latex and urethane rubber latex, natural rubber latex, S
Since the BR latex and the NBR latex are 100 ° C., the above results are obtained.

Regarding the polymerizability of RIM nylon resin,
When flexible sheets made of natural rubber latex and urethane rubber latex were used, RIM nylon did not polymerize at all and did not solidify. When flexible sheets of NBR latex and chloroprene rubber latex are used, RI
Although the M nylon solidifies, the RIM nylon resin in the vicinity of the surface in contact with the flexible sheet was scraped off and easily broken with tweezers, and the polymerizability was poor.
Only acrylic latex and SBR latex were polymerized and solidified by RIM nylon.

The above results are summarized in the table below. In the table, A shows a good result, C shows a bad result, and B shows an intermediate evaluation.

[0035]

[Table 1]

From the above results, when RIM nylon is used as the matrix resin, the flexible sheet is formed from acrylic latex, or at least RIM.
It was confirmed that it is necessary to use acrylic latex for the surface layer that comes into contact with nylon.

[0037]

As is apparent from the above description, according to the method for producing a fiber-reinforced resin product using a RIM nylon resin as a matrix according to the present invention, a flexible mold used as an upper mold for forming a cavity with a mold. Since the flexible sheet is preformed, the inside of the cavity can be quickly raised to the required pressure when pressurized and expanded, and the surplus resin can be smoothly flown to the discharge port. Therefore, a thick portion where excess resin is accumulated does not occur, and a product as designed can be manufactured.

Moreover, since the flexible sheet is formed by the dipping method, it can be formed extremely easily and the thickness of the flexible sheet can be made uniform. Therefore, when the flexible sheet is expanded, the elongation becomes uniform, the pressure is evenly applied to the inside of the cavity to improve the resin permeability, and a uniform product that does not have a resin rich portion and a resin lean portion is manufactured. be able to.

When the flexible sheet is made of acrylic latex, or at least the surface layer on the cavity type surface side is coated with acrylic latex, the polymerization of RIM nylon used as a matrix resin is not hindered and heat resistance is improved. Therefore, it has an advantage that it can be used for a long period of time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a mold according to the present invention.

FIG. 2 is a schematic view showing a method for molding a flexible sheet used in the mold.

FIG. 3 is a cross-sectional view of a conventionally used mold.

FIG. 4 is a cross-sectional view showing a defect of a product molded by the mold.

FIG. 5 is a perspective view of a helmet molded by the mold.

FIG. 6 is a schematic perspective view of a flexible sheet used in the mold.

FIG. 7 is a view showing a manufacturing method for forming the flexible sheet.

[Explanation of symbols]

 10 Mold 11 Lower Mold 12 Mold Surface 13 Fiber Reinforcement Material 14 Flexible Sheet 15 Cavity 20 Injection Port

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29C 45/14 8823-4F 45/26 7158-4F // B29K 77:00 105: 08

Claims (2)

[Claims] 1. A method for producing a fiber reinforced resin product using a nylon resin for reaction injection molding as a matrix, wherein reinforcing fibers are arranged along a mold surface in a cavity of a mold, and then the inner surface shape of the product is formed. A flexible sheet preformed in a corresponding shape, with at least the cavity mold surface that is made of acrylic latex, is attached to the mold so as to form part of the mold cavity, and is used for unreacted reaction injection molding. Nylon resin (RIM nylon resin) is injected into the cavity, then the flexible sheet is externally pressed, and the RIM nylon resin in the cavity is pressed through the flexible sheet to strengthen the RIM nylon resin. A method for producing a fiber-reinforced resin product, which comprises infiltrating fibers to generate a reaction and molding. 2. A fiber-reinforced resin molded article produced by arranging reinforcing fibers in advance in a cavity of a mold and injecting unreacted RIM nylon resin into the cavity to cause a reaction while impregnating the reinforcing fibers. In a mold for production, the cavity is formed by surrounding the cavity with a mold surface of the mold and a flexible sheet having reinforcing fibers arranged in the mold surface and then fixed to the mold. Is preformed into a shape corresponding to the shape of the inner surface of the product, at least the surface layer serving as the cavity mold surface is formed of acrylic latex, and means for externally pressing the flexible sheet is provided. Mold for manufacturing fiber reinforced resin molded products.